JP4273080B2 - Distributed synchronization method in self-organizing wireless communication system - Google Patents

Abstract

A self organizing radio communication system synchronization procedure uses information carrying data packet synchronization sequences in the same or different bursts to data transmitted by some of the mobile stations with reference quality as the synchronization improvement reference

Description

  The invention is at least partly self-organizing radio communication according to the superordinate concept of independent claim 1, i.e. having several mobile stations which are located within the radio coverage of each other via an air interface The present invention relates to a distributed synchronization method in a system.

  The invention further relates to a mobile station in an at least partly self-organizing radio communication system according to the superordinate concept of claim 13.

  Communication systems have great significance not only in the economic domain, but also in the personal domain. Technology development for connecting a cable-connected communication system and a wireless communication system has been actively conducted. Thus, when a hybrid communication system is established, not only the number of services that can be used increases, but also great flexibility can be achieved in terms of communication. Accordingly, devices that can use different systems (multihoming) have been developed.

  In doing so, the wireless communication system provides great technical significance based on the possible mobility of the subscriber.

  In a wireless communication system, information (for example, voice, image information, video information, SMS [Short Message Service Short Message Service] or other data) is transmitted between receiving / transmitting stations (base stations) via a wireless interface using electromagnetic waves. Station to subscriber station). At this time, the electromagnetic wave is emitted at a carrier frequency within a frequency band provided for each system.

  The frequencies 900 MHz, 1800 MHz and 1900 MHz are used for the established global system GSM (Global System for Mobile Communication) of mobile communications. This system essentially transmits voice, telefax and short message service SMS (Short Message Service) as digital data.

  For mobile radio systems having CDMA or TD / CDMA transmission schemes, such as UMTS (Universal Mobile Telecommunication System) or other third generation systems, frequencies in the frequency band of about 2000 MHz are provided. This third generation system has been developed for the purpose of covering the radio domain worldwide and provides a wide range of data transmission services, in particular the radio communication system has only a very small resource interface. It has been developed for the purpose of flexibly managing the capacity of the wireless interface. In this wireless communication system, in particular, the flexible management of the wireless interface allows the subscriber station to send / receive large amounts of data at high data rates when necessary.

  In this wireless communication system, a station accesses a common wireless resource of a transmission medium, for example, time, frequency, transmission efficiency (throughput), or space, is adjusted by a multiple access (MA) scheme.

  In time division multiple access (TDMA), each transmission / reception frequency band is divided into time slots, and one or more time slots that are periodically repeated are assigned to the stations. With TDMA, time, which is a radio resource, is separated into stations.

  In frequency division multiple access (FDMA), the entire frequency region is divided into narrowband regions, where one or more narrowband frequency bands are allocated to the station. According to FDMA, frequencies that are radio resources are separated in a station-specific manner.

  In code division multiple access (CDMA), the transmission efficiency (throughput) / information to be transmitted is encoded in a station-specific manner by means of spreading codes consisting of a number of individual so-called chips, so that the transmission efficiency to be transmitted is (Throughput) is randomly spread over a large frequency region depending on the code. The spreading codes in the cell / base station used by different stations are each orthogonal or nearly orthogonal to each other, so that the receiving station assigns the signal transmission efficiency (throughput) assigned to the receiving station. ) And suppress another signal. With CDMA, transmission efficiency (throughput), which is a radio resource, is uniquely separated by a spread code.

  In Orthogonal Frequency Division Multiple Access (OFDM), data is transmitted over a wide band, where the frequency band is allocated within equidistant orthogonal subcarriers (subcarriers), resulting in subcarriers (subcarriers). ) Simultaneously phase shift, a two-dimensional data stream is formed in the time frequency domain. With OFDM, a frequency, which is a radio resource, is separated in a station-specific manner using orthogonal subcarriers (subcarriers). An integrated data symbol transmitted on orthogonal subcarriers (subcarriers) in one time unit is called an OFDM symbol.

  Multiple access methods may be combined. Then, many wireless communication systems use a combination of TDMA and FDMA systems, and each narrowband frequency band is divided into time slots.

  In the above-described UMTS mobile radio system, a so-called FDD mode (frequency division duplex division duplex) and TDD mode (time division duplex time division duplex) are distinguished. The TDD mode is characterized in particular by being used for signal transmission on the uplink (UL) as well as signal transmission on the downlink (DL), in both transmission directions. Each FDD mode uses different frequency bands.

  In the second and / or third generation wireless communication connection, the information can be transmitted by circuit switching (CS Circuit Switched) or packet switching (PS Packet Switched).

  Connection between the individual stations is performed via a wireless communication interface (air interface). The base station and the radio network controller are components of a base station subsystem (RNS Radio Network Subsystem) as usual. A cellular radio communication system generally has a plurality of base station subsystems connected to a core network (CN Core Network). At that time, the radio network controller of the base station subsystem is generally connected to the access device of the core net.

  In addition to cellular radio communication systems generated in this way, self-organizing wireless radio communication systems, such as so-called Ad Hoc systems, are becoming increasingly important in cellular radio communication systems.

  A self-organizing wireless communication system generally allows direct communication between each mobile terminal device and does not necessarily have a central entity that controls access to the transmission medium.

  With a self-organizing radio communication system, data packets can be exchanged directly between the mobile radio stations without interposing a base station. Therefore, such a wireless network does not require an infrastructure in the form of a base station in the cellular structure. Instead, data packets can be exchanged between mobile radio stations that are within radio range of each other. In order to be able to basically exchange each data packet, it is generally necessary to synchronize between mobile radio stations. That is, in the case of wireless transmission via electromagnetic waves, for example, it is necessary to balance the carrier frequency (frequency synchronization) and the time slot pattern (time synchronization).

  Various solutions can be considered for synchronization in the mobile data radio network. That is, the mobile station can use a common standard transmitted via GPS, for example. Thus, globally known time information that can be followed by all mobile stations is formed in the system (eg, VDL mode 4, WO93 / 01576, “A Position Indicating System”). The disadvantage of this scheme, on the one hand, is that all mobile stations need to use very expensive GPS receivers. On the other hand, GPS signal receivers are not always possible, for example, in buildings. For example, in another system such as TETRA, a master that functions as a “clock generator” for a frequency band assigned to the system can be selected. In any such manner, high granularity for time (TDMA) and / or code (CDMA) is not obtained anyway. The FDMA component is advantageously used for subscriber separation. For example, a third group of systems such as IEEE 802.11 does not operate with a common time slot pattern. The mobile station is synchronized with each received data burst in the form of a one-shot synchronization. Here, in any case, it is no longer possible to reserve resources in the form of time slots in order to guarantee QoS.

  The object of the present invention is to make it possible to synchronize mobile stations and radio communication systems of the type described at the beginning between mobile radio stations for self-organizing data radio networks, and to provide a cellular infrastructure for this purpose. There is to be no. Synchronization is not dependent on GPS and can be generated in a distributed manner outside the center. Nevertheless, the frame structure needs to be supported within a network topology that is highly dependent on time changes, especially when the subscriber mobility is high, i.e. the network topology. Need to be synchronized (for example, in the case of a mobile station in a moving vehicle, see FIG. 1). In addition, in subsequent steps, with respect to synchronization, it is necessary to consider the merge of asynchronously operating clusters, where mobile stations that are located within the mutual radio coverage are called clusters.

  This problem is solved by a method having each requirement according to claim 1, a mobile station having each requirement according to claim 13, and a wireless communication system having each requirement according to claim 15.

  Advantageous embodiments are described in the dependent claims.

  According to the present invention, a synchronization sequence is transmitted from some mobile stations to at least some mobile stations, and some or all of the mobile stations are synchronized to some mobile stations using the synchronization sequence. It is.

  It can be performed in a distributed manner independent of cellular infrastructure and, in particular, base station synchronization. A subscriber station may move but does not necessarily have to move. Hereinafter, this subscriber station is called a mobile station.

  The present invention is particularly suitable for TDD / TDMA-based technology, for example, technology that has become a hot topic for the next generation of mobile communications. For example, the present invention can also be used in the (current) third generation variant of mobile communications, since distributed organized synchronization for high mobile data radio networks is the ULTRA TDD Low Chip Rate (LCR). ) Can be configured for variants. The algorithm port in TSM or HCR can be easily converted. Further, it can be used for other time slot oriented access systems, for example, DECT.

  When the self-organizing radio network coincides with centralized synchronization, within the cluster, the mobile station acts as a clock generator. This role can be determined at the beginning of the network configuration. However, it may be a time limited period. Protocol mechanisms for generating a corresponding mobile station selection are known (see, for example, HIPERLAN 2).

  In the distributed organized synchronization of the present invention, individual mobile stations do not act as clock generators, but a subset of all mobile stations involved serve as clock generators. In extreme cases, all mobile stations can be used to maintain synchronization.

  In addition to the original valid (payload) data, the mobile station also transmits a synchronization sequence. This synchronization sequence is then the part of the data packet that carries the information. However, this synchronization sequence can be utilized in a wireless network by a synchronous channel defining frequency, time and / or code multiplexing that is separately dedicated, i.e. separated from valid data transmission.

The synchronized mobile station detects the synchronization position T _{SYNC, i} of another mobile station and derives the synchronization position of the synchronized mobile station itself from the synchronization position T _{SYNC, i of} this other mobile station. To do. The quality of the individually detected synchronization position (for example, can be derived from the received signal strength at this synchronization position) can then be considered in the same way as the previous synchronization position of the synchronized mobile station.

For the time synchronization position T _SYNC , for example, the following relationship can be set:

In this case, α is a weighting factor for the synchronized position T _SYNCold preceding the synchronized mobile station. There are various strategies for the weight g _i of the actually detected synchronization position of the other mobile station i. The following are two examples:
1. ) Maximum value detection: g _i = 1 Maximum reception level
0 Otherwise, 2. ) Weighting with reception level For the convergence of distributed synchronization, it is particularly important to consider the time of prior synchronization, and therefore advantageously the synchronization is determined in combination with the synchronization position of other mobile stations. It can be seen that In this way, the evaluation value can be improved “continuously” in this way.

  Since the mobile station synchronization time is generally derived from multiple reference points (signal propagation time can be very different based on different distances between individual mobile stations anyway) Unlike synchronization in an organized network (eg, a base station), the synchronization position varies greatly depending on the case. This variation can be taken into account when dimensioning the corresponding guard interval. In the case of a reach of 1 km, for example, an additional permissible deviation of up to 3 μs arises based on the propagation time difference and must be compensated for.

In the following, several alternative embodiments will be described:
A. The transmission of the synchronization data may be in the same burst that carries the data. In so doing, the position of the synchronization data relative to the original data sequence (eg, as a preamble or midamble) is not important.

  B. This method is not based on transmitting synchronous data and the original data sequence together. The synchronization data may optionally be transmitted via another burst (separated from the original data burst by a CDMA, TDMA or FDMA component). What is decisive is simply that the relative position of this burst with respect to the original data burst needs to be uniquely determined.

  C. In order to maintain synchronization, it is important to send the synchronization sequence cyclically (not necessarily periodic). One, several or all mobile stations need to be able to use the “service” of this air interface. This is especially true even if none of the participating mobile stations transmit valid (payload) data. In particular, the cyclic transmission of bursts (hereinafter also referred to as beacons) that also carry a synchronization sequence can be used in distributed synchronization by the method described here, or in the organization of a self-organizing network, for example, within the wireless coverage area. It is very advantageous for identifying the neighbors that are located, as well as for actuating the “neighbor list”.

  D. Each mobile station derives its reference clock from each synchronization signal of each mobile station located within the synchronization reach of each mobile station. The quality of this reference clock can vary greatly. One of the mobile stations uses both a reference clock and a GPS signal, while the other mobile station can derive only the reference clock of the other mobile station from each received signal of the other mobile station. In order to improve the synchronization, for example, the degree of reference clock quality can be indicated in the beacon, whereby it can be taken into account by corresponding weighting in calculating the optimum sampling time point.

  E. For access methods that combine multiple time slots into a so-called superframe within one frame or within several frames, it is necessary to define a mechanism that supports frame synchronization. Here, it is provided to mark each time slot, so that the position within each frame can be estimated from this marking.

  A simple means is, for example, when using another synchronization sequence for the first time slot, as shown in Example 1 in FIG. FIG. 2 shows marking of a synchronization sequence for frame synchronization in Example 1. The disadvantage of this method is that in any case, the period for finding the frame start point is relatively long. In the least advantageous case, it is necessary to wait for a complete frame period until the corresponding sequence defining the frame is repeated (at least one of each subscriber is allowed to generate a beacon in the first time slot). It is assumed that A relatively fast means of frame synchronization is illustrated in Example 2 of FIG. FIG. 3 shows the marking of the synchronization sequence for frame synchronization in Example 2. Here, the synchronization sequence always depends on the position in the frame, that is, a unique synchronization sequence is assigned to each time slot (or a unique synchronization sequence set). Thus, frame synchronization is inherently provided by time slot synchronization. The disadvantage is in any case high calculation costs. That is, it is necessary to provide an autocorrelator for each individual synchronization sequence.

Continuous synchronization-joint synchronization :
Distributed synchronization is characterized by the fact that the synchronization sequence can be transmitted by multiple mobile stations rather than by individual mobile stations. Basically, the synchronization sequences of different mobile stations can be different or cover the same radio resources (determined by frequency band, time slot and / or code). Thus, two types of distributed synchronization are distinguished within the scope of this invention:
-Continuous synchronization-Joint synchronization For the sake of explanation, in the case of both modes, distributed synchronization will be described based on the frame structure defined by 3GPP for UTRA-TDD mode (Low Chip Rate). This is shown schematically in FIG. 4 (3GPP TS 25.221 V4.1.0).

The following explanation is complemented to FIG.
Time slot #n (n is 0 to 6): nth traffic time slot, 864 chip period:
DwPTS: Downlink downlink pilot time slot, 96 chip period;
UpPTS: Up (up) pilot time slot, 160 chip period;
GP: TDD main guard period, 96 chip period;
The selected frame configuration also applies to TSM. Porting to the UTRA-TDD high (fast) chip rate (speed) variant is possible without problems.

Continuous synchronization:
The UTRA-TDD frame structure is optimized for operation within a cellular network. For operation within a self-organizing wireless network, a slight modification is required. In particular, it has been proposed to solve the problem of power impairment so that only one mobile station can start a transmission operation in one time slot. Up to 16 different codes are used to address different receiving mobile stations. Since it is always operated in “down link mode”, different midambles in one time slot can be eliminated. That is, each receiving mobile station is only concerned with the evaluation of a unique communication path. By correlating with the characteristic midamble of each time slot, the timing of each mobile station can be determined relative to its own timing. Averaging over the found synchronization positions shows how much its “time slot pattern” needs to be compensated. To reduce costs, it can operate with the same midamble within all time slots. In any case, for the frame synchronization, one slot needs to be marked specifically, for example a special synchronization sequence is indicated for this slot. Furthermore, in this case, this slot is always used by one mobile station. In other words, frame synchronization cannot be maintained otherwise.

Joint Synchronization:
In addition to the original data transport burst, here the same synchronization sequence / beacon is simultaneously transmitted in one special time slot by a part of the mobile station. By doing so, the cost of synchronization can be significantly simplified.

-Frame synchronization is an intrinsic part of the algorithm,
-It is not necessary to form an expensive average value to find its own synchronization position. The average value formation is performed on the transmission medium by superposition of signals carrying the synchronization sequence, as predetermined.

    The synchronization mechanism is completely identical to the operation in the cellular case, apart from the mobile station sending out the synchronization sequence itself every time.

  In the case of UTRA-TDD LCR, two special synchronization time slots are used. Both can be used meaningfully in the case of joint synchronization. One time slot is used for reception of the synchronization sequence of surrounding mobile stations, and the other time slot is used for transmission of its own synchronization sequence. Thus, all mobile stations can transmit their synchronization sequence once in each frame and simultaneously synchronize within their position in the environment once. If the mobile station synchronizes to an existing cluster, in any case, except for this rule, both possible synchronization time slots can operate in the receiving module. In order to distinguish the synchronization time slots, different synchronization sequences are assigned to the first and second time slots. Each mobile station assigns its synchronization sequence transmissions to time slots with relatively little received power, thus allowing the mobile stations to be assigned to both time slots almost uniformly. In particular, during cluster construction, the second active mobile station is assigned to an unoccupied time slot.

  Refer to FIG. 5 for an illustration of sequential decentralized synchronization (continuous distributed synchronization) and joint decentralized synchronization. Sequential decentralization is shown in the upper part of FIG. 5A of FIG. 5 and joint decentralization is shown in the lower part.

  Consider asynchronous cluster / station synchronization below. In this case, a guard zone method (prisible of the guard zone) is used.

  One of the major challenges of synchronizing within a self-organizing mobile network is shown in FIG. Here, two independent clusters are constructed (each with three stations), and the two clusters are based on their distance (both clusters are located outside their mutual radio coverage) Can operate asynchronously. For example, both clusters cannot be synchronized without criteria such as GPS or mobile radio system base stations. Within the scope of the invention, in particular in the case of “merged” clusters, it becomes possible to adjust the synchronization parameters “locally” before exchanging data between mobile stations of different clusters. .

  The illustrated solution corresponds to a self-organizing radio network with centrally organized synchronization but independent of it.

Data radio coverage and synchronization reach:
In doing so, the data radio coverage defines a range in which a possible receiving station can “just” guarantee a fixed BER. Correspondingly, the synchronization range is defined as the range that an accurate detection of a synchronization parameter such as, for example, a time slice can be guaranteed by a given probability of a receiving station.

Guard zone:
According to the present invention, the synchronization coverage of one station needs to be larger than the combined coverage of valid data (“data radio coverage”). In doing so, the excess reach of the synchronization information defines a so-called guard zone, which advantageously exchanges data between stations of the same cluster, one or more stations of the second close cluster. Can be used to achieve local synchronization of certain system parameters before they are clearly disturbed by the transmission of.

  FIG. 7 shows an active guard zone and passive guard zone scheme. Depending on whether the reference station operates as a transmitting or receiving station, an active or passive guard zone is appropriate. In the first case, i.e. when the active guard zone is commensurate, the guard zone allows all stations in the data radio coverage area to receive the data transmitted by the station N1, and in the second case, i.e. the passive guard zone If appropriate, all stations within the data radio coverage of station N1 can send data without disturbing the second cluster operating asynchronously.

The goal of higher synchronization coverage than the data radio coverage can technically be achieved by the following methods (used for the synchronization sequence):
-Relatively high transmit power (position required in a separate frequency band)
A relatively low modulation index, a relatively high spreading factor when using a band spreading technique, a relatively high receiver sensitivity, a method of determining the (optimal) minimum reception level required for data detection. be able to.

Guard Zone Description for ULTRA TDD LCR Example:
In the following description, the requirements in the active or passive guard zone are considered in detail in the case of a self-organizing network based on UTRA TDD LCR. Assume the following:
-The transmission power S of all stations is the same (UE class 2: 250 mW: 24 dBm)
-The transmission power of the data burst and the synchronization burst is the same-The spreading factor for data is a maximum of 16; the spreading factor for synchronization is 144-Signal-noise ratio (SNR). .
. . For a successful synchronization with 95% probability, δ _S = −7.0 dB,
. . In the case of data detection [delta] _D is - must packet error rate <10 ^-2 is guaranteed - the maximum.

δ _D = 7 dB, which results in Δδ = δ _D −δ _S = 14 dB.
The data reception sensitivity E _D0 is E _D0 = −105 dBm according to the standard.

Reception sensitivity of the synchronization is sensitive than Δδ only _{E D0,} therefore, is Es _{= E D0} -Δδ. To reduce the data reach, (optionally) the reception level E _D required for data detection can be increased by ε _D > 0 dB, ie E _D = E _D0 + ε _D = −105 dBm + ε _D . In the following, two examples are shown. In this case, in the first example, it is necessary to increase the reception level in order to maintain the guard zone, and in the second example, the level is not increased, and therefore the comparison is performed. Large reach can be achieved.

Synchronization reach is determined from the difference between the transmission level and the reception sensitivity _{E S,} therefore, the link for synchronization budget (Link Budget) is
ξ _S = S−E _S = S−E _D0 + Δδ
= 129 dB + Δδ
Correspondingly, the data reach is
ξ _D = S−E _D = S−E _D0 −ε _D = ξ _S −Δδ−ε _D
= 129 dB-ε _D
Is true.

  To that end, consider FIG.

The requirements in the active guard zone will be explained a little using the above diagram. The transmission of data bursts by station N ₁ determines both the data coverage, the synchronous coverage (due to simultaneous transmission of midamble) and thus the guard zone (for station N ₁ ). Station N ₂ is located within the data radio reach of N ₁ . The noise power of the possible noise source (station N ₁ ) needs to be lower by δ _D than the received power of the data packet transmitted by station N ₁ . The propagation loss between the receiving station N ₂ and the possible noise source N ₄ is _D δ + ξ _D accordingly. Between N ₁ and _{N 2,} and on the basis of the different propagation paths between the _{N 4} and _{N 2,} synchronization coverage must be at least _{ξ S = 2ξ D + δ D} . Therefore, the required level for data reception needs to be increased by ε _D = 0.5 (S−E _D0 + δ _S ) = 61 dB and E _D = −44 dBm.

ρ / dB = 32.44 + 20 log ₁₀ (r / km) +20 log ₁₀ (f _c / MHz)
Therefore, the data reachable range <50 m.

In FIG. 9 it is shown that:
Unlike the active guard zone, the passive guard zone does not guard the data reception of a third station located within the data reach of N ₁ but instead of N ₁ from stations such as N ₂ and N _3. Data transmission to the network can be prevented from being greatly disturbed by the neighboring second cluster from the nodes N ₄ , N ₅ , and N ₆ . In this way, the requirements for the guard zone can be greatly simplified. The synchronous reach here is simply ξ _S = ξ _D + δ _D
Need to guarantee the distance. Therefore, in order to increase the reception sensitivity to the minimum reception level for data detection, ε _D = δ _S <0 dB holds. Thereby, it is not necessary to increase the reception sensitivity. A 7 dB reserve remains. The achievable data reach is clearly over 10 km.

In doing so, you can:
• Passive guard zones can achieve significantly higher reach than with active guard zones.
• The cost for synchronization is significantly higher in the passive guard zone. A passive guard zone needs to “guard” a possible transmitting station, that is, to transmit the synchronization sequence of that possible transmitting station on a regular / cyclic basis. This applies in principle to all stations in the cluster. On the other hand, the active guard zone need only be established for the corresponding station immediately before transmission. In order to make efficient use of radio resources, passive guard zones are combined with joint synchronization (where only one resource is commonly occupied by all mobile stations in the cluster).
When operating with different transmit powers, branch into separate frequency bands (and therefore operate at maximum transmit power) or transmit maximum and minimum transmit power for transmission of synchronization sequences It is necessary to consider the difference with the power budget.

In the mobile data money network, distributed synchronization is particularly required when merging two clusters that are synchronized independently of each other, and thus generally asynchronous clusters. According to the present invention, the synchronous reach of one station needs to be larger than the remaining reach of valid data. In so doing, a so-called guard zone is defined by means of an overreach of synchronization information, which advantageously allows data exchange between stations of the same cluster to be carried out by one or more of the neighboring second clusters. It can be used to achieve local synchronization of certain system parameters before being disturbed by transmissions of other stations. The goal of a synchronization range higher than the dataless range can be achieved by the following method (used for the synchronization sequence):
-Relatively high transmit power-relatively low modulation index-relatively high spreading factor when using band spread technology-relatively high receiver sensitivity-(optional) determination of the minimum required reception level for data detection Propose a modified embodiment of:
Distributed slot synchronization for self-organized data wireless networks based on the slotted ALOHA method In a wireless system based on the pure ALOHA method, each subscriber transmits the subscriber's data in a fixed-length data packet after the data is generated. The actual occupancy of the wireless channel is not checked before transmission, so it is likely to collide with transmissions from other subscribers. When the transmissions of two data packets collide, that is, if the time overlaps even a little, the two data packets are lost.

  To clearly improve the number of successful transmissions, the subscriber should only send at a given time. Such a variant of the pure ALOHA method is called slotted ALOHA. For slotted ALOHA, the time interval in which two data packets can collide is halved compared to pure ALOHA.

  A burst transmitted in a time slot in slotted ALOHA has, for example, the structure shown in FIG. In addition to the original data sequence, the burst has at least one additional sequence that is known to both the transmitting and receiving stations and is used for both synchronization and channel evaluation. be able to. Depending on the configuration within this burst, a preamble or midamble is also suitable. This so-called guard period (GP) is also used for propagation time difference compensation as well as subscriber reference clock tolerance. It is usually operated using signal spreading techniques for synchronization. Therefore, the distributed slot synchronization presented at point 3 can be advantageously used for time slot synchronization.

In the figure above:
Figure 1: Network structure of a self-organizing data mobile radio network,
Figure 2: A first example for marking a synchronization sequence for frame synchronization,
Fig. 2: A second example for marking a synchronization sequence for frame synchronization,
Fig. 4: UTRA-TDD mode frame structure (Low Chip Rate),
Figure 5:-Partial view A:
An example of continuous distributed synchronization,
-Partial view B:
Example of uniform distributed synchronization,
Figure 6: Example of two asynchronous clusters,
Figure 7: Active guard zone and passive guard zone diagram
Figure 8: Noise reach of Figure to the active guard zone and three mobile stations _N 4, _{N 5} and _{N 6,}
FIG. 9: Diagram of noise coverage to the passive guard zone and three mobile stations N ₄ , N ₅ and N ₆ ,
Figure 10: Frame structure for UTLA-TDD mode (Low Chip Rate)

Diagram showing the network structure of a self-organizing data mobile radio network The figure which shows the 1st example for marking of the synchronization sequence for a frame synchronization The figure which shows the 2nd example for marking of the synchronization sequence for frame synchronization The figure which shows the frame structure (Low Chip Rate) for UTRA-TDD mode Diagram showing an example of continuous distributed synchronization Diagram showing an example of uniform distributed synchronization Diagram showing examples of two asynchronous clusters Active guard zone and passive guard zone diagram Diagram of noise coverage to active guard zone and three mobile stations N ₄ , N ₅ and N ₆ Passive guard zone and noise coverage to three mobile stations N ₄ , N ₅ and N ₆ The figure which shows the frame structure for UTLA-TDD mode (Low Chip Rate)

Claims (15)

Having several mobile stations located within the mutual radio range via the air interface;
Transmitting at least some of the mobile stations with a synchronization sequence from some of the mobile stations and using the synchronization sequence to synchronize some or all of the mobile stations with some of the mobile stations In a synchronization method in a wireless communication system that self-organizes automatically,
For at least one of the mobile stations, the range of synchronization sequences transmitted is made larger than the range of valid data transmitted by the mobile station and the relatively large synchronization information formed thereby Coverage range, i.e., over-range of synchronization information, defines a guard zone that is used to achieve synchronization before data exchange between each other nearby mobile station is disturbed Method.   The method of claim 1, wherein the synchronization sequence is part of an information transmission data packet.   The method according to claim 1, wherein the synchronization sequence is transmitted through a dedicated synchronization channel.   The synchronized position of the other mobile station is detected by the synchronized mobile station, and the synchronized position of the synchronized mobile station is derived from the synchronized position of the other mobile station. The method according to 1.   The method according to claim 4, wherein the mobile station considers the quality of the individually detected synchronization position and / or the preceding synchronization position of the individually detected synchronization position in order to determine its own synchronization position.   6. A method as claimed in claim 1, wherein the synchronization data is generated in the same burst carrying valid data.   6. A method according to claim 1, wherein the synchronization data is transmitted via another burst separated from the original valid data burst.   8. The method according to claim 1, wherein the synchronization sequence is transmitted cyclically or periodically.   9. A method as claimed in any one of claims 1 to 8, which indicates the degree of quality of the reference data for improved synchronization.   10. A method as claimed in claim 1, wherein the synchronization data is transmitted via another burst separated from the original valid data.   11. A method as claimed in claim 1, wherein synchronization for time slots is used for time frame synchronization.   12. The method according to claim 1, wherein the transmission operation is performed by only one mobile station within one time slot. And means are provided for sending a synchronization sequence, using the synchronization sequence, another mobile station is synchronized, at least in part in the mobile station in a wireless communication system to self-assemble,
Reach of the synchronization sequence to be transmit is the much larger than the reach of the effective data transmitted by the mobile station, a relatively large formed thereby, reach the synchronization information, i.e., the synchronization information A mobile station characterized in that means for defining a guard zone is used in which the excess coverage is used to achieve synchronization before data exchange between each other nearby mobile station is interrupted.   14. A mobile station according to claim 13, wherein means are provided for receiving a synchronization sequence of several mobile stations from several mobile stations.   A radio communication system having a plurality of mobile stations according to claim 13 or 14.

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